One such device is described in published French patent specification No. 1 564 995 (see, in particular, page 13 left-hand column line 43 to page 14 left-hand column line 24, and FIG. 6). In this prior device, the suspension whose liquid phase is to be extracted is injected under pressure into a cylindrical body 221 and is brought into contact with the outer surface of the membrane constituted by a filter cloth 277 applied against a cylindrical metal mesh 270 disposed coaxially inside the body 221. This prior device further includes a cylindrical mesh 282 disposed coaxially inside the space lying between the membrane and the cylindrical body, which mesh is rotated about the axis in order to cause the suspension to rotate relative to the membrane.
This prior device suffers from the drawbacks of being complex and bulky. Pump means are required to inject the suspension into the cylindrical body under pressure. Further, pressurized backwash means are required to remove solid particles from the suspension after they have accumulated on the outside of the membrane.
Preferred embodiments of the present invention provide a compact device for extracting the liquid phase from a suspension.